Accurate localisation is a key goal for any spatial audio reproduction system. Such reproduction systems are highly applicable for conference systems, games, or other virtual environments that benefit from 3D sound. Sound scenes in 3D can be synthesised or captured as a natural sound field. Soundfield signals such as e.g. Ambisonics carry a representation of a desired sound field. The Ambisonics format is based on spherical harmonic decomposition of the soundfield. While the basic Ambisonics format or B-format uses spherical harmonics of order zero and one, the so-called Higher Order Ambisonics (HOA) uses also further spherical harmonics of at least 2nd order. A decoding or rendering process is required to obtain the individual loudspeaker signals from such Ambisonics formatted signals. The spatial arrangement of loudspeakers is referred to as loudspeaker setup herein. However, while known rendering approaches are suitable only for regular loudspeaker setups, arbitrary loudspeaker setups are much more common. If such rendering approaches are applied to arbitrary loudspeaker setups, sound directivity suffers.